Parasitic infections of plants, humans, and other animals pose a worldwide problem. For example, more than 650 million people are at risk for gastrointestinal parasitic infection, and about 200 million are actually infected. Various conditions contribute to the development and spread of parasitic infections, including poor sanitary conditions; low host resistance; population expansion; and inadequate control of vectors and infection reservoirs.
Such parasitic infections present an abundance of medical and social problems. For example, parasitic infection can undermine child development, educational achievement, reproductive health, and social and economic development. Indeed, some parasitic infections can cause morbidity and mortality. Notwithstanding the severe impact that parasitic infections can have, relatively few treatment options are available.
Available treatments are limited, and treatments for some parasitic infections are non-existent. In the 1960s, niclosamide (also known as yomesan) was identified for use in treating certain helminthic parasitic infections; however, niclosamide has certain drawbacks. For example, in many cases a single dose of niclosamide does not provide a curative effect, rather, a relapse ensues because the compound has difficulty accessing cysticercoids buried deeply within the mucosal villi. As such, satisfactory results require an extended treatment with niclosamide for approximately 7 days. See Davis, Drug treatment of intestinal helminthiasis, World Health Organization (WHO), Geneva, 1973.
Another drug that has been used to treat helminthic parasitic infections is Praziquantel (2-(cyclohexylcarbonyl)-1,2,3,6,7,11b-hexahydro-4H-pyrazino(2,1-a)isoquinolin-4-one; also known as Biltracide). See Pearson and Gurrant, Praziquantel: a major advance in anthelminthic therapy. Annals of Internal Medicine, 99:195-198, 1983. Praziquantel can be administered in a single dose; however, treatment strategies making use of Praziquantel are at risk because of the possibility of the development of resistance to Praziquantel. Accordingly, there remains a need in the art for non-harmful compositions that are effective for treating parasitic infections.